Up to seven school children were among nine people injured after a suicide bomber rammed a car packed with explosives into a school bus near an air force base in northwest Pakistan. "About seven children were injured ... [after] a terrorist targeted a school children's bus," said Major-General Waheed Arshad, a military spokesman.

"The driver and the guard who were sitting in the front have been seriously injured," he said.

He said most of the children were saved because of the timely reaction of the driver during the incident about 75km northwest of the capital, Islamabad.

The bomber was killed in the attack.

Checkpoint rammed

The attack came a day after a suicide bomber rammed a car packed with explosives into a police checkpost in the volatile Swat valley in northwest. Pakistan on Sunday, killing six people.